Antibacterial effects of propolis and brood comb extracts on the causative agent of European Foulbrood (Melissococcus plutonius) in honey bees (Apis mellifera)

Abstract

Among a long list of parasites and pathogens that threaten the European honey bee (Apis mellifera), European Foulbrood (EFB) has become an urgent apiary disease, as epidemic outbreaks are becoming increasingly common. EFB is a bacterial disease of larval honey bees, caused by a gram-positive, anaerobic bacterium, Melissococcus plutonius. The most effective current treatment for EFB, oxytetracycline hydrochloride, can disrupt the bee microbiome, cause bee mortality and residues may persist in honey harvested for human consumption. In this study, we explore the efficacy of more sustainable bee-derived solutions, including propolis, honey comb and brood comb ethanol extracts. Using a series of dilutions of these extracts, we determined the minimum inhibitory concertation (MIC) of each bee-derived product on M. plutonius, as well as two model bacterial species, Staphylococcus saprophyticus (gram-positive) and Escherichia coli (gram-negative). Overall, we found that propolis extract was most effective at inhibiting growth of gram-positive bacteria, and that M. plutonious was also susceptible to honey comb (MIC = 16.00 mg/mL) and brood comb (MIC = 45.33 mg/mL) extracts, but at much higher concentrations than that of propolis (MIC = 1.14 mg/mL).

Thinking inside the box: Restoring the propolis envelope facilitates honey bee social immunity

“…Although propolis has recently been shown to inhibit the growth of M. plutonius in vitro (Murray et al BioRxiv [53]), to our knowledge, ours is the first study to observe lower levels of M. plutonius detection in propolis-rich (rough box) colonies, compared to propolis-poor (control) colonies. The significantly lower levels in M. plutonius gene expression that we observed in bees from rough box colonies compared to bees from control colonies corresponded to marginally lower levels of colony signs of EFB in rough box colonies compared to control colonies the following month.…”

Epizootic monitoring of contagious diseases of bees in Rivne region for the period of 2018–2022

“…Тому надзвичайно важливим є контроль за розповсюдженням збудників (Braula coeca, Malpighamoeba mellificae, Nozema apis, Varroa jacobsoni, Varroa destructor, Bacillus larvae, Melissococcus pluton, Enterococcus liquifaecalis, Bacillus alvei, Bacillus latherosporus) найбільш поширених заразних хвороб та ступенем ураження пасік ними. Важливим є організація системи нагляду на державному рівні для виявлення змін у поширеності таких агентів (VanEngelsdrop & Meixner, 2010;Murray et al, 2022;Schäfer et al, 2022;Colwell et al, 2023). Вивченням епізоотичної ситуації на пасіках України з метою запобігання розповсюдженню заразних хвороб бджіл займається Головне управління ДПСС в усіх областях України, регіональні лабораторії ДПСС, ННЦ "Інститут експериментальної і клініч-ної ветеринарної медицини" та "Інститут бджільництва ім.…”